Based on the maximum amount of evaporation monitored over the past 57 years, TCEQ is basing the loss rate at 4.4 acre-feet per acre. Their evaporation chart is attached – note that the yearly amount is generally less than half this amount. Based on the 4.4 rate, this would equate to 8.9 acre-feet or 2.9 million gallons per year for our lake. Any water used for irrigation of the park would offset this amount. See below for our response to TCEQ concerning this subject: The losses are expected to be due to evaporation due to the expanded surface area of Farmers Branch Creek. That loss will be compensated by discharge of additional water (“make-up water”) directly into Farmers Branch Creek. At present, the Town plans to discharge potable water from the Town’s drinking water supply. If the Town elects to replace that discharge with water from a groundwater well, the town will provide information relevant to that water supply to TCEQ and request authorization prior to changing water sources. The discharge will be upstream of the upstream weir. The make-up water will be discharged according to need, rather than continuously, to maintain flow over the downstream weir. A float will be installed at the downstream weir at an elevation above the release level of the weir. The float will control the release of make-up water into the creek. We have reviewed your estimate of a maximum evaporative loss of 13.5 acre-feet per year. That estimate is based on a surface area of 3.06 acres, which is the design area of the impoundment. The existing permit 5383, which allows for impoundment of 1.1019 acre-feet of water, impounds 1.04 acres. That weir will not be modified and only a Change of Ownership is requested for that weir. This project will impound an additional 2.02 acres. Therefore, we anticipate that the maximum evaporative loss will be 4.4 acre-feet/acre X 2.02 acres = 8.9 acre-feet. The make-up water supply and the discharge will be more than adequate to supply that amount of water, if needed. ________________________________ From: Nancy Cline [mailto:ncline@addisontx.gov] Sent: Monday, March 22, 2010 11:52 AM To: Bruce Dunne Cc: Lea Dunn; Clay Barnett Subject: RE: Water rights Bruce, What will the estimated number of treated water be in gallons per year for the “make up” water? Usually, DWU would be compensated for the cost of raw water per month and would this be preferable to us purchasing treated water and then dumping it into the pond? How would the treated water be measured to assure it is the correct amount? Would it be in addition to the proposed irrigation with treated water? IS there a study or submittal to TCEQ that summarizes the options? Thank you, Nancy -----Original Message----- From: Bruce Dunne [mailto:bdunne@icon-engineers.com] Sent: Monday, March 15, 2010 10:16 AM To: Nancy Cline Cc: Lea Dunn; Clay Barnett Subject: RE: Water rights We received a response from TCEQ on our application to “Amend Water Use Permit” on February 4th and have been working with their staff to address their questions. At this time, the only apparent issue to be resolved is “make up” water to account for evaporation. We have proposed to provide “treated” water to account for the evaporation, and evidently, this is not a commonly used method with TCEQ. TCEQ has asked us to provide a more detailed summary of how the recirculation system is going to work and to investigate a possible “dechlorination” method in the event that they determine they will not accept straight treated water for make-up. We anticipate that we should have everything wrapped up in the next several weeks. ________________________________ From: Nancy Cline [mailto:ncline@addisontx.gov] Sent: Thursday, March 11, 2010 5:38 PM To: Bruce Dunne Cc: Lea Dunn; Clay Barnett Subject: Water rights Bruce, Would you please update us on where we stand regarding water rights for the lake? Thank you, Nancy Nancy Straub Cline, P.E. Director of Public Works Town of Addison 16801 Westgrove Drive Addison, TX 75001-2818 Office: (972) 450-2878 P Please consider the environment before printing this email. ****************************************************************************************************************** This e-mail and any files or attachments transmitted with it contains Information that is confidential and privileged. This document may contain Protected Health Information (PHI) or other information that is intended only for the use of the individual(s) and entity(ies) to whom it is addressed. If you are the intended recipient, further disclosures are prohibited without proper authorization. If you are not the intended recipient, any disclosure, copying, printing, or use of this information is strictly prohibited and possibly a violation of federal or state law and regulations. If you have received this information in error, please delete it and notify Hamid Khaleghipour at 972-450-2868 immediately. Thank you. ******************************************************************************************************************* ****************************************************************************************************************** This e-mail and any files or attachments transmitted with it contains Information that is confidential and privileged. This document may contain Protected Health Information (PHI) or other information that is intended only for the use of the individual(s) and entity(ies) to whom it is addressed. If you are the intended recipient, further disclosures are prohibited without proper authorization. If you are not the intended recipient, any disclosure, copying, printing, or use of this information is strictly prohibited and possibly a violation of federal or state law and regulations. If you have received this information in error, please delete it and notify Hamid Khaleghipour at 972-450-2868 immediately. Thank you. *******************************************************************************************************************